[media] Remove outdated TODO.

The issue mentioned in this TODO was already completed in the associated
bug.

Bug: 869660
Change-Id: I57f35558770a0c56441a899371eff5d723d76a26
Reviewed-on: https://chromium-review.googlesource.com/c/1371076Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Commit-Queue: Dan Sanders <sandersd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615678}

content/renderer/media/webrtc/rtc_video_decoder_adapter.cc

@@ -43,10 +43,6 @@ namespace content {
 namespace {
 
 // Any reasonable size, will be overridden by the decoder anyway.
-//
-// TODO(sandersd): DXVA VDA does not compute a visible rect itself; we should
-// not enable RTCVideoDecoderAdapter on Windows until that is fixed.
-// https://crbug.com/869660.
 const gfx::Size kDefaultSize(640, 480);
 
 // Assumed pixel format of the encoded content. WebRTC doesn't tell us, and in